US3550645A - Wire wound armature,method and apparatus for making same - Google Patents

Description

United States Patent Inventor Raymond J. Keogh Huntington, N.Y. Appl. No. 798,496 Filed Oct. 3, 1968 Division of Ser. No. 620, 306, Mar. 3, 1967, abandoned. Patented 29,1970 Assignee Photocireuits Corporation Glen Cove, N.Y.

[$4] -WIRE WOUND ARMATURE, METHOD AND APPARATUS FOR MAKING SAME 6 Claims, 7 Drawing Figs.

US. Cl 140/912, 29/605 Int. Cl B2lf 3/00 Field of Search 140/92.1, 92.2, 93; 29/205, 605; 242/5, 7.04, 7.15, 7.16; 72/127, 133

[56] References Cited UNlTED STATES PATENTS 667,134 1/1901 Lundskog. 140/922 804,250 I 1/1905 Miller 140/922 2,368,389 1/1945 Von Knauf 29/605 3,346,021 10/1967 Ross... 140/922 Primary ExaminerLowe1l A. Larson Attorney-Morgan, Finnegan, Durham and Pine ABSTRACT: A wire wound motor armature constructed by forming successive groups of single turn armature coils, the coils within each group being in registry with one another, the groups being indexed relative to one another, and all coils being interconnected in a wave configuration.

The apparatus for forming the winding including a rotating winding form and a wire dispensing stylus moving radially, the movements of the form and the stylus being coordinated to form the winding.

msc MOTOR DRIVE CONTROL UNI T PROGRAM INPUT mimsnumslsn 3.550.645

- SHEETEOF4 m6 INVENTOR.

1% 0 RAYMOND 1.1mm

F I63 w w WM P05 I T/ON SENSING 5TYL us MWOR DRIVE 5 o/sc MOTOR 97/ DRIVE con/mm.

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PROGRAM INVENTUR.

INPUT RAYMOND J KEOGH A T TORNE Y5 cal fashion.

PW IRE WOUND ARMATURE, METHOD AND APPARATUS FOR MAKING SAME v This application is a divisional of copending application Ser.

No. 620,306 filed Mar. 3, 1967 in the name of Raymond J. Keogh, now abandoned.

BACKGROUND OF INVENTION In the construction of electric motor armatures it has been generally accepted that the coil span of the individual arma- ;ing results. By having the coil span slightly different from the distance between magnetic pole centers there is a slight indexing of the winding with each successive armature coil and, as a result, the coils each have the same configuration and are uniformly distributed over the armature surface in a symmetri- In conventional DC machines the armature is usually formed with multiturn, preformed coils which are placed in coil slots of a laminated iron core. Since the winding must conform to the armature slot locations, it is desirable to have a uniform indexing of the winding with respect to each successive coil such that all coils have the same shape and allslots contain the same number of conductors. v

In recent years the low inertia, printed circuit type of motor has been developed eliminating the iron and coil slots in the armature. The printed circuit motor usually includes a discshaped armature in which radially extending arrays of conductors are usually bonded to opposite sides of an insulating carrier. The conductor patterns for the armature are formed either by chemical techniques i.e. plating, or etching, or by mechanical stamping techniques. The restrictions upon the winding configurations in a printed circuit motor are even more severe than in the case of a conventional motor. For example, a two-layer printed circuit armature must be formed with single turn coils, the winding must be retrogressive and each coil must index the winding so that all coils have the same configuration.

' The printed circuit motor has the advantages of high acceleration and smooth torque, but, because of the single turn coils, can only operate at relatively low voltages.

In a copending application, Ser. No. 511,608 filed Dec. 6, I965, in the name of Robert Page Burr, having a common assigneewith this application, an insulated wire wound type of motor is illustrated as well as the methods for making the same. This armature can be formed by depositing insulated wire around positioning pins by means of a wire dispensing stylus. Each successive coil, which can be single or multiturn, indexes the winding slightly to obtain a uniformly progressive or retrogressive winding distributed around the positioning pins. This type of armature if constructed with multiturn armature coils can operate at higher voltages but is difficult to construct with automatic machinery because it is necessary to constantly reverse the winding direction while forming the multiturn coils.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to an improved winding technique for wire wound armatures which do not include slots for the armature coils as well as the apparatus for making the winding.

"The armature is formed by depositing insulated wire, preferably around positioning pins, following a pattern forming a plurality of single turn coils which are all in registry and thus, if the pattern is continued, successive armature loops would occupy approximately the same positions. Instead ofindexing the winding with the formation of each successive armature coil, the winding is indexed only after a predetermined number of coils have been formed in registry with one another.

BRIEF DESCRIPTION OF THE DRAWINGS An illustrative embodiment of the invention is set forth in the drawings which form part of the specification and wherein;

FIG. 1 is a perspective assembly drawing of the motor; FIG. 2 is a cross-sectional view of the assembled motor; FIGS. 3A3D are a series of diagrams illustrating the armature winding sequence;

FIG. 4 is a schematic illustration of winding apparatus for forming the armature.

ARMATURE CONSTRQCTION GENERALLY The rotating winding for disc 'machine includes a large number of radia'lly extending insulated wire segments distributed to form an annular-array which will be adjacent the stationary magnetic pole faces in the completed machine. These radially extending segments are interconnected to form a continuous winding which is substantially planar, or in other words, is in the form of a relatively thin disc. Successive radially extending segments of the winding are displaced by a distance approximately equal to the distance between pole centers of the associated magnetic structure and are interconnected so that current flowing in the winding will flow in one direction across the south poles and in the opposite direction across the north poles.

The radially extending segments are preferably arranged to minimize the crossing of conductors to thereby minimize the thickness of the armature disc within the magnetic airgap. The thinnest possible winding configuration would occur where all radially extending segments are substantially radial. However, when automatic winding'techniques are employed, it is often preferable to have the radially extending segments somewhat skewed.

The portions of the winding which interconnect the radially extending segments and which lie outside the annular airgap area have a thickness at least twice the diameter of the conductors. As the crossover areas of the armature winding are decreased in width, for example, to reduce the diameter of the armature, additional stacking of the conductors occurs and hence the thickness of the armature winding in these areas increases. However, the crossover connections, by definition, are not within the working airgap of the machine and, therefore, this increased thickness is not detrimental to the performance of the machine.

The winding is formed in a continuous fashion utilizing insulated wire and, since the conductors are insulated, it is possible to cross conductors as desired. The copper distribution can be controlled to achieve a low copper density in the area of the airgap and a higher copper density in the thicker crossover areas outside the airgap. This control over the relative copper density permits the designer to optimize performance for a particular size armature disc.

An armature turn is the portion of the winding including two successive radially extending segments. When the arma ture is constructed in accordance with this invention the armature coils are eachsingle turn coils, and, therefore, each armature coil likewise includes two successive radially extending segments. An armature loop is a portion of the winding which spans approximately 360? of the armature. Thus, with an eight-pole machine an armature loop includes four successive armature coils whereas with a l2-pole machine an armature loop includes six successive armature coils.

If the armature coils comprising a loop are in registry, the armature loop spans exactly 360 and if successive armature loops are in registry with the first, the successive armature loops occupy essentially the same positions. For the purpose of this invention, armature coils are defined as being in regis try where they are part of an armature loop which, if completed, would be in registry with the prior armature loop or portions thereof. Indexing of the winding occurs when successive armature loops or portions thereof lie in positions adjacent prior armature loops.

FIGS. 3A-3D illustrate the step by step formation of an armature winding for an eight-pole machine including i l7 armature coils and nine commutator segments. The winding is formed about a jig or die including inner and outer rows of positioning pins. each such row including 27 pins. The inner pins are designated 111-270 and the outer pins are likewise designated lb-27b. The tabs for connection to the commutator segments are designated A-L in the order of connection. Since the armature is for an eight-pole machine, each annature loop includes four armature coils. Since there are 27 positioning pins each armature coil spans approximately eight positioning pins. Since there are 117 coils and nine commutator segments every l3th coil is connected to the commutator.

The armature winding commences by attaching the insulated wire to one of the commutator connection tabs designated as tab A. Tab A is in radial alignment with the first set of positioning pins 1a and lb. The winding then passes outside positioning pins 2a, 3b, 4b and 5b in succession. The first armature coil is then completed by passing the wire inside pin 70.

Next, the second armature coil is formed by passing the wire inside pin 80, outside pins lob-12b, and inside pin 14a. The winding continues by then forming the third and fourth annature coils by passing inside pin 1511, outside pins l7bl9b, inside pins Zla and 22a, outside pins 24b--26b and inside pin Ia. At this point the first armature loop spanning 360 is complete is completed as is illustrated in FIG. 3A.

The second armature loop is in registry with the first armature loop and is formed following the same sequence around the positioning pins as shown in FIG. 3B. The third armature loop is also in registry as well as the first coil of the fourth armature loop. The winding as it appears after formation of 3% armature loops l3 coils) is shown in FIG. 3C. Each of the 13 coils in the first group are in registry with one another and follow the same pattern about the positioning pins.

A commutator pull out is formed following the first group of i3 coils by passing the winding around tab B. At this point the winding is also indexed so that the second group of 13 coils will lie in positions adjacent the first group.

The winding progresses by passing outside pin 8a, outside pins 9b 1 lb, inside pins 130 and 14a, outside pins l6b-l8b, inside pins 200 and 21a, outside pins 23b25b and inside pin 27a. The winding as it then appears after completion of four armature loops (l6 coils), including three coils of the second group, is shown in FIG. 3D. Coils 14-16 of the second group are indexed relative to coils I- l 3 of the first group.

The winding sequence for the entire 1 17 coil armature is set forth in Table I.

TABLE I Start of Outer End of 0011 plus 0011 Loop 4.

TABLE I-Continued Start of coil Outer pins End of coil Second Pullout, Second Index Point Third Pullout, Third Index Point NH I-H ouozom tetou i 1 Nut- Mi i- NHH w-cnoowwsuoowwmom-m sweetness:

Seventh Pullout, Seventh Index Point Eighth Pullout, Eighth Index Point Fifth Pullout, Fifth Index Point Sixth Pullout, Sixth Index Point Loop 7.

Loop 8.

Loop 9.

... 9o Uzieu zao sam z Loop 10.

Loop 11.

Loop 12.

Loop 13.

Loop 14.

Loop 15.

Loop 18.

Loop 19.

Loop 20.

Loop 21.

Loop 22.

Loop 23.

Loop 24.

Loop 25.

1 Loop 21. 22

Loop 17. I

TABLE I-Contlnued Outer End of For simplicity the number of commutator segments should be a submultiple of the number of armature turns. lf dead coils Start are to be avoided. the number of commutator segments must coi ins c011 be odd ift the number of pole pairs is even and vice versa. Furthermore, the commutator connection points should occur f: i at regularly spaced intervals throughout the armature spaced 9 11-13 by a number of complete armature loops plus or minus one ar- ,3 i mature turn. Thus. the coil AC spacing between commutator g g Loop 0 connection points can be expressed. 16 18-20 22 22 24-46 27,A Closing Coil. Y=h(p) :l: 1 (4) wherein Y equals the number of armature turns between commutator connection points, p equals the pairs of poles 15 (also number of armature turns per armature loop), n is an in- ARMATURE DESIGN CONSIDERATIONS teger multipler and the or sign is chosen to yield a progres- In designing an armature certain factors must be known at swe or f f wmdmg asdes'red' th: outset These factors are for example: Table ll indicates the number of conductors required ln the The outside diameter of the armature; armature for an eight-pole machine having vanous combina- 2 The number of pole pairs in the magnetic Structure; trons or of commutator segments and distances between com- The flux level which will be produced by the magnetic mutator connection points in accordance with the relationstructure; Sh'p: 4. The desired voltage constant for the annature, that is, the Y= (P) 'l" 1 TABLE II first? uilzlil Jitt "uiltt %.?113El $354 No. of commutator (5 conduc- (9 conduc- (13 condue- (17 conduc- (21 conduc- (25 conducsegments tor pairs) tor pairs) tor pairs) tor pails tor pairs) tor pairs) voltage generated by the armature per 1000 r. .m., From Table ll it can be seen that an armature having 13 com- 5. The winding resistance. mutator segments and commutator connection points spaced These factors are interrelated, and, particularly factors 3, 4 by 2 /tarmature loops (9 armature turns or conductor pairs) and 5 must be compatible ifa reasonable armature is to result. would have a tot l of 117 rm turns; n rm ure with For the armature shown in FlGS. 3A3D these factors are nine commutator segments and a spacing between commutaan outside armature diameter of 3.6 inches, four pole pairs tor connection points of 3% loops (i3 conductor pairs or ar- (eight poles), a flux level of 5.3 kilogauss as can be obtained mature turns) would also have a total of 1 l7 armature turns; with Alnico permanent magnets, a voltage constant of 2.2 and an armature with seven commutator segments and a spacvolts per 1000 r.p.m., and a winding resistance of 2 ohms end ing between commutator connection points of 4% armature to end. loops (l7 conductor pairs or armature turns) would include a The number of armature conductors can be determined by total of 119 armature turns. Any of these three combinations the following formula: could be used for the armature under consideration wherein p N X the desired number of armature turns is approximately 1 16.

k, (1) A similar table could be developed for an eight-pole machine with the spacing between commutator connection wherein it, equals volts/rad/sec; p equals number of pole pairs, p nts according to h f a l equals flux per pole in Maxwells, and N equals the number y=n(p) 1 (6) of conductor pairs or armature turns. 7

Substituting the aforementioned factors into Formula 1 proln this arrangement the commutator connection points would id h f ll i occur at V4, 1%, 2%, etc., armature loops. From this additional table other combinations can be found which could be used in k w 2 the design of an armature having approximately 116 armature coils.

For the armature shown in FIGS. 3A--3D the combination voltlrad'lsec' (3) of nine commutator segments and commutator connection Thus, it is determined that approximately 97 conductor pairs p in p r ed y armature loops armature turns) (armature turns) provides 0.022 volt/rad/sec which in turn is has n lected which provides an armature with a total of equal to approximately 2.2 volts per 1000 rpm. 1 l7 armature turns this selection being sufficiently close to Formula 1 assumes an armature coil shape which is caret d sir d number ofarmature turns.

j fully selected to conform to the shape of the magnets forming The Criteria for the location of the indexing points is the the stator poles. in the interest of simplicity and winding speed same as that for the location of commutator connection asimplified configuration has been adopted as shown in FIGS. p ints, and hence is represented by Formula 4. For con- 3A-3D which is approximately 80 percent efficient. Thus, to venience, the indexing points are normally selected to coinobtain the desired characteristics the number of annature cide with the commutator connection points since it is possiturns is increased by a factor of 1.2, and hence, approximately ble to make both the commutator connection and to index the ll6armature turns are required. winding as part of the same step in the winding sequence.

However, the commutator connection points and the indexing points need not coincide nor need the coil spacing between commutator connection points be the same as that between successive indexing points.

The number of positioning pins used in forming the armature must be a multiple of both the number of commutator segments and the number of indexing points. In the armature under consideration, the number of commutator segments has been selected as nine and the number of indexing points is also nine. Accordingly, the armature can be constructed using a number of positioning pins which is a multiple of nine. A better winding distribution occurs as the number of positioning pins increases, but as the number of positioning pins increases, the complexity of the armature winding apparatus also increases. Furthermore, a practical limit is reached when the spacing between positioning pins of the inner row approaches 10 pins per inch. For the winding under consideration a multiplier of three has been selected and hence there are 27 positioning pins.

The wire size is determined by measuring the approximate length of an armature turn, multiplying this length by the number of turns in the armature to obtain the total armature length, and by then consulting a wire table to select a wire size which provides the desired armature resistance. From a standard copper wire table number 28 guage wire is found satisfactory for the armature under consideration, having a resistance of2 ohms end to end.

In many cases it is desirable to construct the armature using multistrand insulated wire as this tends to provide a thinner more evenly distributed winding. Such an armature can be formed by dispensing multistrand wire as the armature is formed. The same armature can also be made by repeating the entire windingsequence several times with a single strand of wire. A pair of 3l gauge copper wires would provide essentially the same electrical characteristics for the winding under consideration.

The winding technique in accordance with the invention is quite flexible and is highly desirable since a large number of different armatures can be made utilizing the same automatic winding apparatus and can often be made using the same winding forms, i.e. winding forms with the same number of positioning pins.

MOTOR ASSEMBLY An insulated wire wound disc-type motor in accordance with one embodiment of this invention is shown in FIGS. land 2. The motor is enclosed within a two-part housing 1 including a base plate 2. A stationary permanent magnet structure 3, brush holders 4 and one of the bearings 5 are mounted on the base plate. The other bearing 6 is mounted within a central opening in the cup-shaped member 7 forming the other part of the motor housing, member 7 being secured to the base plate at its periphery be means of screws 8.

The motor shaft 9 is journaled in bearings 5 and 6, and includes an intermediate section 10 of increased diameter. The increased diameter section is positioned between the bearings and prevents axial movement of the shaft. The motor armature 14 is mounted on shaft 9 by means of a flanged hub 11 rigidly secured to the shaft and an associated flanged nut 12 which cooperates with the external threads on the shank portion of the hub. The dielectric disc 17 forming part of armature 14 is rigidly secured between the flanges of nut 12 and hub 11.

The armature winding constructed as described in relation to FIGS. 3A3D is supported on a dielectric disc 17 shown adjacent the winding for illustration purposes. The commutator segments 16 are centrally located with respect to the winding and are secured to dielectric disc 17. The flange of hub 11 provides structural backing for the commutator to prevent distortion ofthe armature disc due to the force exerted against the commutator by the brushes.

The motor illustrated in FIGS. 1 and 2 is an eight-pole motor and therefore the permanent magnet structure 3 is divided into eight segments which provide the necessary pole faces. The permanent magnet structure is a unitary ringshaped member provided with slots 20 which define individual bosses that form an annular array of the pole faces lyingin a plane perpendicular to the axis of rotation. The magnetic structure is a cast or sintered unit fashioned from a nickel-aluminum-cobalt alloy such as Alnico. The structure is magnetized to provide pole faces of alternating magnetic polarities. A ring 18 of soft iron is secured to the rear of the housing by screws 19 to complete the magnetic path between adjacent pole faces. The space between ring 18 and the pole face surfaces is the working airgap of the machine and must be sufficient to accommodate the armature and provide a working clearance. I

A few turns of heavy, insulated wire, referred to as a charging winding, are placed around the individual pole pieces prior to final assembly. Charging winding 39 passes outside one pole piece 22, through a slot 20, and then inside the next pole piece 21, etc., twice around the unit. This winding in effect surrounds one pole piece in a clockwise direction, and surrounds the adjacent pole piece in the counterclockwise direction and, therefore, current flow through the charging winding tends to produce poles of alternating magnetic polarity. After flnal assembly the charging winding is energized to magnetize the permanent magnets.

The radially extending segments of the armature winding lie within the working airgap adjacent the pole faces. The thickness of this portion of the armature winding within the airgap is maintained at a minimum. The thicker portions of the winding which include the crossover connections are located outside the airgap.

Brush holders 4 each include an insulated sleeve having a cylindrical body portion 25, the end of which extends through suitable openings 27. The brushes 29 are rectangular in cross section and extend from the brush holders through suitably dimensioned rectangular openings 28. The end of the brush holder opposite the rectangular opening is internally threaded and adapted to receive a flat head screw 32. When the screw is inserted, pressure is applied to the brush via a spring 30 and small pressure plate 31, so that the brush is maintained in engagement with commutator segments 16. The number of brushes and the placement relative to the pole faces varies in accordance with the armature winding and current carrying requirements.

WINDING APPARATUS The armature can be constructed by distributing insulated wire upon a planar surface in continuous fashion. This is accomplished using a winding form 40 as shown in FIG. 4 having appropriately positioned pins 41 extending upwardly from the planar surface so that the insulated wires forming the armature can be wound around the pins. The pins are located in two concentric rows. The positioning pins in the inner row are designated 1a-27a, and the positioning pins in the outer row are designated 1b-27b, thereby corresponding to those shown in FIGS. 3A-3D.

The insulated wire can be distributed directly upon the planar surface of the winding form, or upon a disc blank 44 as shown. Holes are drilled or punched into the disc blank corresponding to the positions of the positioning pins and, hence, when the blank is dropped into position as shown in FIG. 4, the pins extend upwardly through the blank. The disc blank includes the commutator segments 45 secured to the disc surrounding a central opening which will accommodate the motor shaft and hub structure. Each commutator segment includes an upwardly extending tab, these tabs being used to position the commutator pullout loops of the winding.

Winding form 40 is coupled to a motor 50 which rotates the winding form in the clockwise direction. A position sensing unit 51 is coupled to the motor shaft and provides electrical signals indicating the instantaneous position of the winding form.

The insulated wire is dispersed by a stylus 52 mechanically coupled to a lead screw 53 which moves the stylus radially relative to the winding form, The movement of the stylus is controlled by a bidirectional, variable speed motor 54 coupled to the lead screw.

The operation of motors 50 and 54 is controlled from a control unit 56, respectively, via a disc motor drive 57 and a stylus motor drive 58. The control unit operates in accordance with a preselected program to coordinate the movements of the winding form and the stylus toform the desired winding configuration. The entire armature winding is formed while the winding form rotates in a single direction, and hence, since it is not necessary to periodically reverse the direction, relatively high winding speeds are readily attainable. As the winding form rotates, position sensing unit 51 provides signals indicating the position of the winding form, and these signals are compared with the program to control the corresponding radial movements of the stylus.

The winding forms and control programs are preferably interchangeable so that the same winding apparatus can form armatures of various sizes and various configurations.

After the insulated wire has been distributed to form the winding it is necessary to give it structural integrity so that the winding can be mounted on the motor shaft. There is no sigthereof:

l. The winding is formed upon the surface of a ther moplastic disc blank as shown in FIG. 4, and when completed, heat and pressure are applied to press the winding into the disc blank. The winding, particularly in -the annular airgap area, is embedded in the disc and has a thickness no greater than the insulated wire. The same result can be achieved for forming the winding without the disc blank and thereafter pressing the thermoplastic disc down upon the preformed winding.

2. The winding can be laminated between a pair of thermoplastic discs. The winding is performed and thereafter placed between the laminated discs, or can be wound upon one of the disc blanks as shown in FIG. 4. Preferably, the structure is compressed in the airgap area to minimize the thickness.

3. The winding can be formed directly upon the winding form without a disc blank and thereafter coated, as by spraying, dipping or the like, with a suitable dielectric medium to provide structural integrity.

4. The winding can be formed directly upon the winding form without a disc blank and thereafter spotted with an adhesive material to bond the insulated wires at points where the conductors cross.

5. The winding can be formed with a heavy gauge wire which by itself possesses sufficient structural integrity.

SPECIFIC ARMATURE DESIGNS There are a substantial number of possible armature designs within the scope of the invention. Several specific examples, in addition to that previously described, are as follows:

EXAMPLE NO. I

The positions of the commutator pullouts need not coincide with the positions of the index points. A winding sequence for such an armature could be:

start at a commutator connection;

wind one full annature loop;

index ahead two pins;

wind I armature loops;

form a commutator pullout;

repeat. The parameters and predicted operating characteristics for such an armature are as follows:

Number of Poles 8 Number of Commutator Segments 27 Number of Armature Conductors 594 Number of Armature Turns 297 Number of Positioning Pins per row 81 Number of Armature Turns Between Indexing Points 11 Number of Armature Turns Between Commutator Pullouts 11 Type of Winding Progressive Wire Size #30 A.W.G. Outside Diameter of Armature "inches" 3. 6 Inside Diameter of Armature do 2. 0 ArmatureResistance (including brushes) -ohms- 1. 9 Field Flux -kiloga.uss 5 Voltage Constant, K v./k. .m.-- 5. 5 Torque Constant, K, -in.-oz. amp 7. 4 Dumping Constant, K in.-oz./k.p.m 0. 18

EXAMPLE N0. 2

The indexing points can be separated by less than a complete armature loop as indicated, for example, by formula 6 when n equals one. For a machine including four pole pairs the armature winding sequence would be:

start at a commutator connection;

wind it of an armature loop;

index backward (retrogressive);

form a commutator pullout;

repeat.

The parameters and predicted operating characteristics for such an armature are as follows:

Number of Poles Number of Commutator Segments 35 Number of Conductors 210 Number of Turns Number of Pius in Form (Outer Row) 105 Number of Turns Between Indexing Points 3 Number of Turns Between Commutator Segments 3 Type of Winding Retrogressive Wire Size #24 A.W.G. Outside Diameter of Armature iuches 6. 6 Inside Diameter of Armature do 3. 5 Armature Resistance (Excluding Brushes) -ohm 0. 3 Field Flux kilogauss 3. 8 Voltage Constant, K v./k.p.m. 5. 5 Torque Constant, K in.-oz./amp 7. 4 Damping Constant, K in.-oz./k.p.m 1. 21

EXAMPLE No. 3

Number of Poles 8 Number of Commutator Segments Number of Conductors 150 Number of Turns 75 Number of Pins in Form (outer row) 45 Number of Turns Between Indexing Points- 10 Number of Turns Between Commutator Segments 10 Type of Winding Retrogressive Wire Size Double Strand (Bifilar) #28 A.W.G. Outside Diameter of Armature inches 3 6 Inside Diameter of Armature d 2. 0 Armature Resistance (Excluding Brushes) ohms 0. 25 Field Flux ki1ogauss 5 Voltage Constant, K v./k.p.m 1. 4 Torque Constant, K in.-oz./amp 1. 89 Damping Constant, K in.-oz./k.p.m 0. 176

EXAMPLE NO. 4

Number of Poles 8 Number of Commutator Segments 11 Number of Conductors 154 Number of Turns 77 Number of Pins in Form (Outer Row) 44 Number of Turns Between Indexing Points 7 Number of Turns Between Commutator Segments T pe of Winding Progressive ire Size Double Strand (Bifilar) #28 A.W.G. Outside Diameter of Armature inches 3. 6 Inside Diameter of Armature do 2. 0 Armature Resistance (Excluding Brushes) ohms 0. 255 Field Flux -kilogauss 5. 5 Voltage Constant, K. v./k.p.m 1. 44 Torque Constant, K in.-oz./amp 1. 94 Damping Constant, K in.-oz./k.p.m' 0. 181

EXAMPLE NO. 5

Number of Poles 8 Number of Commutator Segments 17 Number of Conductors 442 Number of Turns 221 Number of Pins in Form (Outer Row) 68 Number of Turns Between Indexing Points" 13 Number of Turns Between Commutator Segments Type of Winding Retrogressive Wire Size Double Strand (Bifilar) #28 A.W.G. Outside Diameter of Armature inches 3. 6 Inside Diameter of Armature do 2. 0

5 Armature Resistance (Excluding Brushes) ohms- 0. 74 Field Flux A kilogauss- 5. 5 Voltage Constant, K v./k.p.m 4. 14 Torque Constant, K in.-oz./amp 5. 60 Damping Constant, K .in.-oz./k.p.m 0. 52

EXAMPLE-NO. 6

15 The distance between commutator connection points can be different from the distance between indexing points. A winding sequence for such an armature could be:

start at a commutator connection; wind 2% armature loops; index ahead one positioning pin;

wind one armature loop; form commutator pullout; winding 1% armature loops (total of 4% loops) from beginning;

index ahead one positioning pin;

wind two armature loops;

form commutator pullout;

continue sequence, indexing after every 2% armature loops,

and forming a commutator pullout after every 3% armature loops.

The parameters and predicted operating characteristics for such an armature are as follows:

Number of poles 8 5 Number of Commutator Segments 9 Number of Armature Conductors 234 Number of Armature Turns 117 Number of Positioning Pins Per Row 27 Number of Armature Turns Between Indexing Points Number of Armature Turns Between Commutator Connection Points 13 Type of Winding Retrogressive Wire Size 28 A.W.G. Outside Diameter of Armature inches 3. 6 Inside Diameter of Armature -do- 2 Armature Resistance (including brushes) -ohms- 0. 5 Field Flux kilogauss 5. 3 Voltage Constant, K v./k.p.m 2. 2 Torque Constant, K in.-oz., amp 2. 9 Damping Constant, K in./k.p.m 1

While several specific embodiments have been described in detail it should be obvious that there are numerous other embodiments within the scope of the invention. The invention is applicable to cylindrical armatures as well as disc shaped armatures, and is more particularly defined in the appended claims. 0 1 claim:

1. Apparatus for forming an armature comprising: a rotatable form including a plurality of circular rows of positioning pins; 1 a wire dispensing stylus for depositing wire around said positioning pins, said stylus being adapted substantially for radial movement relative to said form; and control means for rotating said form in a single direction and coordinating the movement of said stylus so that insulated wire is distributed in continuous fashion about said positioning pins by said stylus to form successive groups of single turn armature coils, all coils within a group being in registry and each including a pair of radially extending winding segments displaced by a distance approximately in accordance with distance between adjacent pole cen- 3 ters of the intended stator for the armature, the winding is indexed after formation of each successive group so that one group of coils lies in coil positions adjacent those of a 'prior group of coils.

2. Apparatus according to claim 1 wherein said rotatable form includes two concentric rows of positioning pins.

3. Apparatus according to claim 1 vwherein said rotatable form is adapted to receive a dielectric disc form, and said wire dispensing stylus deposits wire upon said dielectric disc form. t

4. Apparatus for forming an armature comprising:

a rotatable formincluding a plurality of concentric rows of positioning pins and a concentric row of commutator connection points;

a wire dispensing stylus for depositing insulated wire around said positioning pins and commutator connection points, said stylus being adapted for radial movement relative to said form; and

control means for rotating said form in a single direction and coordinating the movement of said stylus so that insulated wire is distributed in continuous fashion about said positioning pins by said stylus to form successive groups of single turn armature coils, all coils within a group being in registry and each including a pair of radially extending winding segments displaced by a distance approximately in accordance with distance between adjacent pole centers of the intended stator for the armature, the winding is indexed after formation of each successive group so that one group of coils lies in coil positions adjacent those of a prior group of coils; and commutator connection loops are formed around said commutator connection points.

5. Apparatus according to claim 4 wherein said rotatable form is adapted to receive a dielectric disc form having commutator segments secured thereto, said commutator connection points being tab's extending from said commutator segments, and wherein said wire dispensing stylus deposits said insulated wire upon said dielectric disc form.

6. Apparatus according to claim 4 wherein said control means is programable to provide different winding configurations.

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